Methods of interfacing to match fiber optic waveguides of differing refractive indexes is well known in the art but the typical mechanically angled optical interface has many complications associated with their use. Along with effecting wavelength and polarization they are difficult to fabricate, hard to align, and generate transmission losses. This invention uses a simple 90 degree interface with a stand-off and avoids these problems.
Reflections in fiberoptic systems degrade performance. They can lead to temporal dispersion, background noise, losses, crosstalk, laser instabilities and other problems. Reflections can arise from many sources such as switch and device interfaces, receiver termination, and other connections. Reflection requirements are becoming more and more demanding given such products as dense LAN's and test equipment. Return loss is one of the most important specifications in many optical devices. Traditional fixes are relatively complex and expensive. For example, a large refractive index discontinuity occurs between a fiber and a gradient index (GRIN) lens. This discontinuity can create a return loss of 30 dB. The standard industry method to fix this problem is to angle both the fiber and the GRIN lens. This can create a return loss of greater the 50 dB. Using the approach of this invention with parts that are easy to fabricate and assemble return losses of greater then 40 dB can be achieved.